Biomedical subjects

Yu-Qiu Zhang

Publications and source records attributed to Yu-Qiu Zhang.

29 records · Page 2Linked to original sources

PubMed2004

Identification and characterization of a rat novel gene RSEP4 expressed specifically in central nervous system.

The low-abundantly expressed genes composed the majorities of the mRNAs expressed in the central nervous system (CNS), and were thought to be important for the normal brain functions. Through differential screening a low-abundance cDNA sublibrary with mRNA from neuropathic pain of chronic constriction injury (CCI) model, we have identified a novel rat gene, rat spinal-cord expression protein 4 gene (RSEP4). The total length of RSEP4 cDNA is 2006 bp, with a 501 nucleotide open reading frame (ORF) that encodes a 167 amino acid polypeptide. Northern blot revealed that RSEP4 was expressed specifically in the CNS. In situ hybridization showed that the mRNA of RSEP4 was strongly expressed in the CA1, CA2, CA3 and DG regions of hippocampus, the Purkinje cells of cerebellum, and the small sensory neurons of dorsal horn and large motor neurons of ventral horn of spinal cord. Over-expression of RSEP4-EGFP fusion protein in the human embryonic kidney 293T cells showed that RSEP4 protein was mainly localized in the cell cytoplasm. These results suggest that RSEP4 may play some roles in the CNS.

Amino Acid Sequence↗

PubMed2003

Involvement of spinal neurokinin-1 receptors in the maintenance but not induction of carrageenan-induced thermal hyperalgesia in the rat.

The study was undertaken to assess the antihyperalgesic effect of L-732,138, (N-acetyl-L-tryptophan-3,5-bistrifluoromethyl benzyl ester), a non-peptide neurokinin-1 (NK1) receptor antagonist in rats when given intrathecally. The peripheral inflammation associated with behavioral hyperalgesia to a thermal stimulus was induced by intraplantar (i.pl.) injection of carrageenan. The thermal hyperalgesia was measured by paw withdrawal latency. Intrathecal (i.t.) injection of L-732,138 (100 nmol) at 3h after carrageenan markedly attenuated the paw withdrawal latency of the inflamed paw, but not that of the non-inflamed paw. L-732,138 (100 nmol, i.t.) given 10 min prior to carrageenan injection had no effect on the carrageenan-induced decrease in paw withdrawal latency to noxious thermal stimulus. The results demonstrate that NK1 receptor is involved in the maintenance but not the induction and development of thermal hyperalgesia evoked by carrageenan.

Animals↗

PubMed2003

Kynurenic acid enhances electroacupuncture analgesia in normal and carrageenan-injected rats.

The interaction between electroacupuncture (EA) and an intrathecally administered wide-spectrum excitatory amino acid (EAA) receptor(s) antagonist, kynurenic acid (KYNA) on carrageenan-induced thermal hyperalgesia and spinal Fos expression was investigated. Intrathecal (i.t.) injection of 0.1, 1, 10, and 100 nmol KYNA markedly and dose-dependently increased the latency of paw withdrawal (PWL) of the carrageenan-injected paw. While the PWLs of the non-injected and normal saline (NS)-injected paws were not obviously affected by application of KYNA at the doses tested. Intrathecal injection of 0.1 nmol KYNA significantly potentiated the anti-nociception induced by EA stimulation of contralateral 'Zu-San-Li' and 'Kun-Lun' acupoints either in the carrageenan- or NS-injected rats. Three hours after intraplantar (i.pl.) injection of carrageenan, the number of Fos-like immunoreactive (Fos-LI) neurons was significantly increased in all layers of ipsilateral spinal cord at L(4)-L(5) with the higher density in laminae I-II and V-VI. Intrathecally pre-administered KYNA (10 nmol) significantly reduced the total number of carrageenan-induced Fos-LI neurons with more apparent reduction in laminae I-II and IV-V. Pre-coapplication of 10 nmol KYNA and EA of bilateral 'Zu-San-Li' and 'Kun-Lun' acupoints, the numbers of carrageenan-induced Fos-LI neurons in laminae I-II and V-VI further reduced. The level of Fos expression in the spinal cord induced by carrageenan was significantly lower compared with that of i.t. injection of KYNA or EA alone. These results demonstrated that EAA receptor(s) antagonist could enhance EA-induced anti-nociception and anti-hyperalgesia.

Animals↗

PubMed2003

The rostral ventromedial medulla mediates the facilitatory effect of microinjected orphanin FQ in the periaqueductal gray on spinal nociceptive transmission in rats.

Single unit extracellular recordings from spinal dorsal horn neurons were obtained with glass micropipettes in pentobarbital-anesthetized rats. A total of 50 wide dynamic range (WDR) neurons were studied in 25 rats. Microinjection of orphanin FQ (OFQ, 0.1 microg/0.1 microl) (a potent endogenous ligand of the opioid receptor-like receptor (ORL-1)) into the ipsilateral ventrolateral parts of periaqueductal gray (vlPAG) significantly increased C-response and post-discharge activity in most of the WDR neurons. Pre-microinjection of lidocaine (4%) into the nucleus raphe magnus (NRM) (0.5 microl), ipsilateral nucleus reticularis gigantocellularis (NGC) (0.6 microl), or nucleus gigantocellularis pars alpha (NGCalpha) and nucleus reticularis paragigantocellularis lateralis (NPGL) (0.5 microl) markedly reduced intra-vlPAG microinjection of OFQ-induced facilitatory effects on nociceptive responses of WDR neurons. Furthermore, if the NRM and ipsilateral NGC were simultaneously pre-microinjected with lidocaine, the intra-vlPAG microinjection of OFQ-induced facilitation on nociceptive responses of WDR neurons was eliminated. Also, a similar effect was observed when all the NRM, ipsilateral NGC, NGCalpha and NPGL were blocked with lidocaine. No significant effect on nociceptive responses of WDR neurons per se was found after blocking the NRM, ipsilateral NGC, NGCalpha/NPGL, or all the NRM, ipsilateral NGC, and NGCalpha/NPGL with lidocaine. These results indicate that (1) the facilitatory effect evoked by microinjection of OFQ into the vlPAG on nociceptive responses of WDR neurons in the spinal dorsal horn is primarily mediated by the NRM and ipsilateral NGC; (2) the NRM, ipsilateral NGC, and NGCalpha/NPGL do not mediate tonic descending inhibition of the spinal dorsal horn neurons.

Action Potentials↗

PubMed2003

[Anterior cingulate cortex and processing of pain].

Anterior cingulate cortex (ACC), an important part of the limbic system, has extensive connections with other cortical areas and subcortical nuclei and is involved in modulating many functions. In recent years, an increasing body of evidence in eletrophysiology, functional imaging and behavioral study indicates that ACC is closely involved in processing of pain, especially in the affective dimension of pain. This review will focus on the progress in the study of ACC in processing of pain.

Animals↗

PubMed2002

Expression of 5-HT(2A) receptor mRNA in some nuclei of brain stem enhanced in monoarthritic rats.

The present study was designed to investigate the expression of 5-hydroxytryptamine (5-HT) (2A) receptor mRNA in the nucleus of raphe magnus (NRM), ventrolateral periaqueductal gray (vlPAG) and dorsal raphe nucleus (DRN) in a monoarthritic rat model using an in situ hybridization technique. 5-HT(2A) receptor mRNA was expressed with low to moderate levels in NRM, vlPAG and DRN. After complete Freund's adjuvant (CFA)-induced monoarthritis, a significant increase in 5-HT(2A) receptor mRNA expression was observed in bilateral NRM, vlPAG and DRN, and the change lasted, at least, for 2 weeks. This result indicates that the synthesis of 5-HT(2A) receptor is enhanced in bilateral NRM, vlPAG and DRN of monoarthritic rats, suggesting that 5-HT(2A) receptor is involved in the central regulation of pain transmission following CFA-induced chronic inflammation.

Animals↗

PubMed2002

Age-related alterations in responses of the nucleus basalis magnocellularis neurons to frontal cortex stimulation in rats.

The present study investigated the age-related alterations in responses of the nucleus basalis magnocellularis (nbM) neurons to frontal cortex (FCX) stimulation. Single unit extracellular recording from the nbM neurons were obtained with glass micropipettes in urethane-anesthetized rats. A total of 137 units were located within the nbM in the three age groups (young, 3 months; adult, 12 months; old, 24 months). FCX stimulation elicited responses in 91% of the 137 neurons. Most of them were excited. The frequency of occurrence of excitatory responses in the nbM neurons was decreased with aging. The thresholds and latencies of excitatory responses evoked by FCX stimulation were increased in old rats. The mean peak-firing rate of exciting phase was gradually reduced with aging. These findings indicate that there might be some functional changes in the nbM neurons with aging.

Aging↗

PubMed2002

Thermal hyperalgesic effects induced by intracerebroventricular injection of interleukin-1beta in rats.

The present study was to investigate the effects of intracerebroventricular (i.c.v.) injection of interleukin-1beta (IL-1beta) on thermal nociception in SD rats. The rats were divided into control and drug-administration groups. The animals of control group were given vehicle solution via i.c.v. injection. The animals of drug-administered groups were given IL-1beta at different doses (5, 50 and 500 pg/kg b.w.) via i.c.v. injection. IL-1 receptor antagonist (IL-1ra, 50 ng/kg) was injected 20 min before injection of IL-1beta or vehicle solution. The nociceptive threshold, which was represented as paw withdrawal latency (PWL), to a noxious thermal stimulation was measured using an analgesiameter. I.c.v. injection of IL-1beta dose-dependently shortened the PWL. At the dose of 500 pg/kg, the shortening of the PWL occurred at 20 min, reaching a peak within 40 min, lasted 100 min after injection, then gradually returned to the baseline level. Pretreatment with IL-1ra completely blocked the effects of IL-1beta-induced shortening in PWL. The results obtained suggest that IL-1beta may induce hyperalgesia in rats through binding to IL-1 receptors in the brain.

Animals↗

PubMed2002

Inhibitory effects of intrathecally administered interleukin-1beta on carrageenan-induced hyperalgesia and spinal c-Fos expression in rats.

The present study investigated the effects of interleukin-1beta (IL-1beta) injected intrathecally (i.t.) on carrageenan-induced thermal hyperalgesia and spinal c-Fos expression. The paw withdrawal latency (PWL) by the thermal stimulus was taken as an index of the thermal hyperalgesia of rats. I.t. injection of 10 ng IL-1beta significantly increased the PWL of the carrageenan-injected paw. Expression of c-Fos induced by intraplantar (i.pl.) injection of carrageenan was examined in the spinal cord with immunohistochemical methods. Three hours after i.pl. injection of carrageenan, the number of c-Fos-like immunoreactive (c-Fos-LI) neurons was significantly increased in laminae I-II, III-IV and V-VI of the ipsilateral spinal cord at L4-5 with the higher density in laminae I-II and V-VI. I.t. pre-injected IL-1beta significantly decreased the number of carrageenan-induced c-Fos-LI neurons in laminae I-II in the ipsilateral spinal cord and also inhibited the hyperalgesia induced by i.pl. carrageenan. These results suggested that i.t. injection of IL-1beta suppressed the central nociceptive input into laminae I-II and produced an antinociceptive effect.

Afferent Pathways↗

PubMed2002

Expression of 5-HT1A receptor mRNA in rat lumbar spinal dorsal horn neurons after peripheral inflammation.

The present study observed the expression of the 5-hydroxytryptamine (5-HT) (1A) receptor mRNA in the lumbar spinal dorsal horn neurons following carrageenan inflammation using in situ hybridization (ISH). We also studied the co-localization of 5-HT(1A) receptor mRNA and gamma-amino butyric acid (GABA) or enkephalin (ENK) immunoreactivities using a combined fluorescent ISH and immunofluorescent histochemical double-staining technique. The finding of this study demonstrated that 5-HT(1A) receptor mRNA was widely distributed in the spinal dorsal horn with the highest density in laminae III-VI. Following carrageenan-induced inflammation, the 5-HT(1A) receptor mRNA expression in all layers of ipsilateral dorsal horn was significantly enhanced, and the peak occurred after 8h. Furthermore, the number of 5-HT(1A) receptor mRNA and GABA or ENK immunoreactive double-labeled cells was also markedly increased 8h after carrageenan injection. These findings suggested that following peripheral inflammation, the synthesis of 5-HT(1A) receptor was increased in the lumbar spinal dorsal horn neurons, especially in spinal GABA and ENK neurons.

Animals↗

PubMed2002

Excitatory amino acid receptor antagonists and electroacupuncture synergetically inhibit carrageenan-induced behavioral hyperalgesia and spinal fos expression in rats.

The interaction between electroacupuncture and an N-methyl-D-aspartic acid (NMDA) receptor antagonist, (DL-2-amino-5-phosphonopentanoic acid; AP5), or an (+/-)-alpha-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid/kainite (AMPA/KA) receptor antagonist, (6,7-dinitroquinoxaline-2,3 (1H,4H); DNQX) administered intrathecally on carrageenan-induced thermal hyperalgesia and spinal c-Fos expression was investigated. The latency of paw withdrawal (PWL) from a thermal stimulus was used as a measure of hyperalgesia in awake rats. Intrathecal (i.t.) injection of 1 and 10 nmol AP5, but not DNQX, markedly increased the PWL of the carrageenan-injected paw. At a dose of 100 nmol, either AP5 or DNQX significantly increased the PWL of carrageenan-injected paw, with AP5 being more potent. The PWLs of the non-injected and normal saline (NS)-injected paws were not detectably affected by the administration of NMDA or AMPA/KA receptor antagonists at the doses tested. Unilateral electroacupuncture stimulation of the 'Zu-San-Li' (St 36) and 'Kun-Lun' (UB 60) acupuncture points (60 and 2 Hz alternately, 1-2-3 mA) contralateral to the carrageenan-injected paw significantly elevated the PWLs of carrageenan- and NS-injected paws. Although neither i.t. injection of 0.1 nmol AP5 nor 1 nmol DNQX alone had an effect on the PWL of the carrageenan- and NS-injected paws, both significantly potentiated electroacupuncture-induced analgesia in carrageenan-injected rats, especially 0.1 nmol AP5. Fos expression evoked by intraplantar (i.pl.) injection of carrageenan was examined in the spinal cord with immunohistochemical methods. Three hours after i.pl. injection of carrageenan, the number of Fos-like immunoreactive (Fos-LI) neurons was significantly increased in all the layers of the ipsilateral spinal cord at L(4-5), with the highest density in laminae I-II and V-VI. Intrathecally pre-administered AP5 (10 nmol) or DNQX (100 nmol) significantly reduced the total number of carrageenan-induced Fos-LI neurons. The reduction was most apparent in laminae I-II and IV-V. Similarly, following bilateral electroacupuncture stimulation of the 'Zu-San-Li' and 'Kun-Lun' acupuncture points, the numbers of carrageenan-induced Fos-LI neurons in laminae I-II and V-VI were also markedly reduced. When a combination of electroacupuncture with 10 nmol AP5 or 100 nmol DNQX was used, the level of Fos expression in the spinal cord induced by carrageenan was significantly lower than electroacupuncture or i.t. injection of AP5 or DNQX alone. These results demonstrate that electroacupuncture and NMDA or AMPA/KA receptor antagonists have a synergetic anti-nociceptive action against inflammatory pain. Furthermore, this study supports the idea that both NMDA and AMPA/KA receptors are involved in spinal nociceptive transmission in carrageenan-inflamed rats, with the former more preferentially mediating transmission of nociceptive information from cutaneous tissue.

Animals↗